Method for controlling trap generation of SNMP

ABSTRACT

A method for controlling trap generation of an SNMP which is operated between a manager and at least one agent, wherein a TrapFlag field and a Trap Peer field are defined for each management-object resource (each object) in describing an MIB of an SNMP and more than two objects are correlated to define a trap generation condition, so that trap generation can be effectively controlled by defining a trap behavior individually for an object of an SNMP MIB.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an SNMP (Simple NetworkManagement Protocol), and more particularly, to a method for controllingtrap generation of an SNMP.

[0003] 2. Description of the Background Art

[0004] One of network management protocols for a communication networkmanagement, the SNMP defines a control structure for a management-objectresource (an object) on the basis of an RFC 1157 standard.

[0005]FIG. 1 shows a construction of a manager and an agent adopting anSNMP in accordance with a conventional art.

[0006] As shown in FIG. 1, the SNMP is adopted in the communicationnetwork consisting of a central SNMP management system (manager) 10 andat least one SNMP management-object system (agent) 12.

[0007] The manager 10 serves to control a management-object resource(object) of the agent 12 through the SNMP. That is, the manager 10outputs an object access message (GET/SET/GETNEXT) to the agent 12 andperforms searching, changing, generating or deleting on the objectdefined in an MIB (Managed Information Base) of the agent 12.

[0008] The GET message is a message to read a data from the MIB 14, andthe MET message is a message to write a data in the MIB 14. The GETNEXTmessage is a message to read an object next to the object read by theGET message. A GETResponse is a message to transmit the data read fromthe MIB 14 to the manager 10 according to the GET/GETNEXT message.

[0009] Accordingly, when the manager 10 searches information, ittransmits an OID (Object ID) together with the object access message(GET/GETNEXT) to the agent 12, and the agent 12 transmits theGETResponse message including a value of the corresponding data togetherwith the OID back to the manager 10. In this respect, the OID is the IDof the object, and every data is discriminated by the OID.

[0010] The SNMP supports a ‘Trap’ operation so that the agent 12voluntarily transmits information on the object to the manager 10,without depending on the request of the manager 10.

[0011] Describing a management object behavior, access authorization andgrammar structure allowable for the object existing in the MIB 14, theSNMP defines a trap in the MIB 14 by relating an object to be subjectedto trap generation to a condition of the trap generation. The trap isdefined as follows:

[0012] ObjectName TRAP-TYPE

[0013] ENTERPRISE {enterprise name}

[0014] VARIABLES {variable name}

[0015] DESCRIPTION “comment”

[0016] ::=Sub OID

[0017] Accordingly, when the state (i.e., system up/down and systemdisturbance) of the object is changed, the agent 12 voluntarily outputsa TRAP PDU (Protocol Data Unit) to inform the manager 10 of the statechange of the object. In this respect, the TRAP PDU includes an OID anda corresponding data value.

[0018] The network management protocol through the SNMP will now bedescribed in detail.

[0019] The manager 10 outputs an ID of the object (OID) together withthe GET message to the agent 12 in order to search the state of theobject of the agent 12. At this time, the OID is an ID of each object,by which every management-objected data is discriminated.

[0020] Upon receipt of the GET request, the agetn 12 reads a data valuefrom the MIB 14 and transmits the GETResponse message to the manager 10.The GETResponse message includes a pair of an OID and a read data (OIDand a read data) form.

[0021] The manager 10 outputs the next OID together with the GETNEXTmessage in order to search the next object, and in response, the manager12 transmits the GETResponse message in the same form to the MANAGER 10.This operation is repeatedly performed so as for the manager 10 tosearch the state of the every object.

[0022] When the manager 10 writes a data in the MIB 14, it outputs anOID of the object and a SET message, and the agent searches a targetdata by using the OID and changes a corresponding data value.

[0023] Meanwhile, unlike the GET/GETNEXT/SET message, the trapmanagement behavior is used for the agent 12 voluntarily report thestate of the object periodically. That is, after the agent 12 relates aspecific data and a trap generation condition, when it comes to apredetermined cycle, the agent 12 outputs a trap PDU (Potocol Data Unit)to inform the manger 10 of the change in the state of the object. Also,the TRAP PDU consists of a pair of an OID and a data, the same as thatof the GETResponse message.

[0024] However, in the SNMP standard-based MIB technique of theconventional art, the object to be subjected to the trap generation isstatically defined. Accordingly, conventionally, since the trapoperation is adoptable only to the object defined in the MIB, themanager is not able to add or delete a specific object as an object asnecessary during the network management operation. In addition, once atrap condition is defined in the MIB, a trap operation is applied toevery defined object, resulting in that the agent generates a TRAP PDUeven for a object with little state change.

[0025] Thus, the agent generates a trap more than necessary and thus themanager should process numerous TRAP PDU transmitted from the pluralityof agents, so that the traffic is increased. This works as a factor todegrade the management efficiency in the management network using theSNMP

SUMMARY OF THE INVENTION

[0026] Therefore, an object of the present invention is to provide amethod for controlling trap generation which is capable of effectivelycontrolling trap generation by defining a trap behavior individually foran object of an SNMP MIB.

[0027] To achieve these and other advantages and in accordance with thepurpose of the present invention, as embodied and broadly describedherein, there is provided a method for controlling trap generation of anSNMP operated between a manager and at least one agent, wherein aTrapFlag field and a Trap Peer field are defined for eachmanagement-object resource (each object) in describing an MIB of an SNMPand more than two objects are correlated to define a trap generationcondition.

[0028] To achieve the above object, there is provided a method forcontrolling trap generation of an SNMP which is operated between amanager and at least one agent, including the steps of: defining aTrapFlag field and a TrapPeer field in an MIB of an agent; setting aTrapFlag field value according to the message outputted from themanager; setting a TrapPeer field value for each object by the agentaccording to the Trap generation condition defined in the MIB; andgenerating a trap for an object according to the values of the TrapFlagfield and the TrapPeer field.

[0029] To achieve the above object, there is provided a method forcontrolling trap generation of an SNMP including the steps of: defininga TrapFlag field and a TrapPeer field in an MIB of an agent; andgenerating a trap for an object according to the values of the TrapFlagfield and the TrapPeer field as defined.

[0030] In the method for controlling trap generation of an SNMP, thestep of generating a trap includes the sub-steps of: searching theTrapFlag field of each object when it comes to a trap generation period;checking a state of the TrapPeer field in case that the TrapFlag is inan ‘ON’ state; and generating a trap for a corresponding object in casethat the TrapPeer is in an ‘ON’ state.

[0031] The foregoing and other objects, features, aspects and advantagesof the present invention will become more apparent from the followingdetailed description of the present invention when taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which are included to provide afurther understanding of the invention and are incorporated in andconstitute a part of this specification, illustrate embodiments of theinvention and together with the description serve to explain theprinciples of the invention.

[0033] In the drawings:

[0034]FIG. 1 shows a construction of a manager and an agent adopting anSNMP in accordance with a conventional art;

[0035]FIG. 2 shows a construction of a manager and an agent adopting anSNMP in accordance with the present invention; and

[0036]FIG. 3 is a flow chart of a method for controlling trap generationof the SNMP performed in the agent of FIG. 2 in accordance with thepresent invention.

[0037]FIG. 4 is a detail flow chart of a method for generating a trap inthe trap generating step S4 of FIG. 3 in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Reference will now be made in detail to the preferred embodimentsof the present invention, examples of which are illustrated in theaccompanying drawings.

[0039] In the present invention, when a trap object is described in anMIB of the SNMP, trap-related information is additionally defined foreach object. The trap-related information is defined by adding thefollowing fields in an MIB technique document.

[0040] 1. TrapFlag Field

[0041] A TrapFlag field is a field representing whether a trap is to begenerated or not for an object described in the MIB. The TrapFlag fieldis set to be turned on or off by the manager.

[0042] In case that the TrapFlag field is in an ON state, the agentgenerates a TRAP PDU for the corresponding object, while, in case thatthe TrapFlag field is in an OFF state, the agent does not generate aTRAP PDU for the corresponding object.

[0043] Accordingly, when an object of which state is little changedduring a network management operation is generated, the TrapFlag fieldof the corresponding object is set to be ‘ON”, so that, even though aspecific object is not deleted from the management target, the sameeffect can be obtained.

[0044] 2. TrapPeer Field

[0045] A TrapPeer field is a field defining a trap generation conditionfor an object, which is set by ‘ON’ state (logic ‘1’) or ‘OFF’ state(logic ‘0’) by the agent. That is, in case that the state of an objectsatisfies a trap generation condition, the agent sets a TrapPeer fieldas the ‘ON’ state.

[0046] In this respect, the trap generation condition can be defined bycorrelating more than two objects. For example, in case that an object‘B’ is greater than ‘n’ and an object ‘C’ is greater than ‘m’, aTrapPeer field is defined to be set as the ‘ON’ state. Consequently,without adding an object, the same effect can be obtained.

[0047] Accordingly, when the TrapFlag field and the TrapPeer field areall in the ‘ON’ state, the agent generates a TRAP PDU for thecorresponding object.

[0048] The trap generation process in the SNMP will now be described.

[0049] As shown in FIG. 3, the manager 20 defines a trap as shown inbelow by correlating objects, trap generation conditions, a TrapFlagfield, and a TrapPeer field (S1).

[0050] ObjectName TRAP-TYPE

[0051] ENTERPRISE {enterprise name}

[0052] VARIABLES {variable name}

[0053] DESCRIPTION “comment”

[0054] TRAPFLAG {flag value}

[0055] TRAPPEER {flag value}

[0056] ::=Sub OID

[0057] For example, objects ‘A’ and ‘B’ are set and a trap generationcondition can be defined as follows.

[0058] 1) A value of the object ‘A’ is in the range of 1˜5

[0059] 2) If the value of the object ‘A’ is greater than ‘3’, a TRAP PDUis basically generated.

[0060] 3) If the value of the object ‘B’ is greater than 4, a value ofthe TrapPeer field of the object ‘A’ is set to be ‘ON’.

[0061] And, the manager 20 outputs a TrapFlag setting signal to theagent 22 during network management to set a TrapFlag field value (S2).That is, the manager 20 sets a TrapFlag field of an object which showslittle state change ordinarily as ‘OFF’ so as to count it out from anobject list.

[0062] At this time, the process of the transmission of the objectaccess message (GET/SET/GETNEXT) from the manager 20 to the agent 12 andthe transmission of the GETresponse from the agent to the manager 20 isthe same as in the conventional art, descriptions of which are thusomitted.

[0063] The agent 22 sets a value of the TrapPeer field of each objectaccording to a trap generation condition as defined during networkoperation (S3).

[0064] Thereafter, when the report period comes, first, the agent 22generates a trap for each object according to the values of the TrapFlagfield and the TrapPeer field (S4). That is, as shown in FIG. 4, first,the agent 22 searches the TrapFlag field of the object ‘A’ to checkwhether a corresponding TrapFlag is in an ‘ON’ state (ST11).

[0065] If the TrapFlag of the corresponding object ‘A’ is in an ‘OFF’state, even though the trap generation condition 2) is satisfied, theagent does not generate a trap. Meanwhile, in case that the TrapFlag isin an ‘ON’ state, it is checked whether the TrapPeer is in an ‘ON’ state(ST12). Upon checking, in case that the TrapPeer is in an ‘ON’ state,the agent 22 generates a trap for the object ‘A’ and performs a normaloperation (ST13 and (ST14).

[0066] In this manner, a trap is generated by conditions for the morethan two objects by using two fields. And, though a single agent istaken as an example for an explanation's sake in the present invention,a plurality of agents can be connected to the manager.

[0067] As so far described, according to the a method for controllingtrap generation of an SNMP of the present invention, a TrapFlag fieldand a TrapPeer field are separately defined for each object in the MIB,and more than two objects are correlated to define trap generationconditions.

[0068] Accordingly, there is an effect that an object can be added ordeleted as necessary, and especially, trap generation can be arbitrarilycontrolled.

[0069] In addition, the periodical management behavior does notperformed for the object of which state is not changed, so that atraffic of the management behavior can be reduced.

[0070] Moreover, the agent is controlled and the state change ismonitored by using the SNMP having the trap ON/OFF fields by objects, sothat management efficiency in the management network can be increased.

[0071] As the present invention may be embodied in several forms withoutdeparting from the spirit or essential characteristics thereof, itshould also be understood that the above-described embodiments are notlimited by any of the details of the foregoing description, unlessotherwise specified, but rather should be construed broadly within itsspirit and scope as defined in the appended claims, and therefore allchanges and modifications that fall within the meets and bounds of theclaims, or equivalence of such meets and bounds are therefore intendedto be embraced by the appended claims.

What is claimed is:
 1. A method for controlling trap generation of anSNMP which is operated between a manager and at least one agent, whereina TrapFlag field and a Trap Peer field are defined for eachmanagement-object resource (each object) in describing an MIB of an SNMPand more than two objects are correlated to define a trap generationcondition.
 2. The method according to claim 1 , wherein the TrapFlagfield is a field for indicating whether a trap is to be generated foreach object described in the MIB.
 3. The method according to claim 1 ,wherein a value of the TrapFlag field is set as ‘ON’ state or ‘OFF’state by the manager.
 4. The method according to claim 3 , wherein theagent generates a trap for a corresponding object in case that theTrapFlag field is in the ‘ON’ state, while, the agent does not generatea trap in case that the TrapFlag field is in the ‘OFF’ state.
 5. Themethod according to claim 1 , wherein the TrapPeer field is a field fordefining a trap generation condition for an object.
 6. The methodaccording to claim 5 , wherein the TrapPeer field is set as an ‘ON’state or an ‘OFF’ state by the agent.
 7. The method according to claim 6, wherein the agent sets the TrapPeer field as the ‘ON’ state in casethat the state of an object satisfies a trap generation condition. 8.The method according to claim 7 , wherein the trap generaiton conditionis defined by correlating more than two objects.
 9. A method forcontrolling trap generation of an SNMP which is operated between amanager and at least one agent, comprising the steps of: defining aTrapFlag field and a TrapPeer field in an MIB of an agent; setting aTrapFlag field value according to the message outputted from themanager; setting a TrapPeer field value for each object by the agentaccording to the Trap generation condition defined in the MIB; andgenerating a trap for an object according to the values of the TrapFlagfield and the TrapPeer field.
 10. The method according to claim 9 ,wherein the TrapFlag field is a field for indicating whether a trap isto be generated for each object described in the MIB.
 11. The methodaccording to claim 9 , wherein the TrapPeer field is a field fordefining a trap generation condition for an object.
 12. The methodaccording to claim 9 , wherein the agent sets the TrapPeer field as the‘ON’ state in case that the state of an object satisfies a trapgeneration condition.
 13. The method according to claim 9 , wherein thetrap generation condition is defined by correlating more than twoobjects.
 14. The method according to claim 9 , wherein the trapgenerating step comprising the sub-steps of: searching a TrapFlag fieldof each object when it comes to a trap generation period; checking thestate of a TrapPeer field in case that the TrapFlag is in an ‘ON’ state;and generating a trap for a corresponding object in case that theTrapPeer is in the ‘ON’ state.
 15. The method according to claim 14 ,wherein in case that the TrapFalg is in the ‘OFF’ state, a trap is notgenerated in no case.
 16. The method according to claim 14 , wherein incase that the TrapFlag is in the ‘ON’ state and the TrapPeer is in the‘OFF’ state, a trap is not generated.
 17. A method for controlling trapgeneration of an SNMP comprising the steps of: defining a TrapFlag fieldand a TrapPeer field in an MIB of an agent; and generating a trap for anobject according to the values of the TrapFlag field and the TrapPeerfield as defined, of which the step of generating a trap comprising thesub-steps of: searching the TrapFlag field of each object when it comesto a trap generation period; c hecking a state of the TrapPeer field incase that the TrapFlag is in an ON state; and generating a trap for acorresponding object in case that the TrapPeer is in an ON state. 18.The method according to claim 17 , wherein the TrapFlag field is a fieldfor indicating whether a trap is to be generated for each objectdescribed in the MIB.
 19. The method according to claim 17 , wherein theTrapPeer field is a field for defining a trap generation condition foran object.
 20. The method according to claim 17 , further comprising thesteps of: setting a TrapFlag field value according to a messageoutputted from the manager; and setting a TrapPeer field value for eachobject in the agent according to the trap generation conditions definedin the MIB.
 21. The method according to claim 20 , wherein the manageroutputs a message to set a TrapFlag field of an object of which state isnot changed as an ‘OFF’ state.
 22. The method according to claim 20 ,wherein the trap generation condition is defined by correlating morethan two objects.
 23. The method according to claim 20 , wherein theagent sets the TrapPeer field as the ‘ON’ state in case that the stateof an object satisfies a trap generation condition.